The present invention relates to an improved cooling fan structure, and more particularly to a cooling fan structure. In which, the vane assembly and the fixed base seat contact with each other at one single point and an air bearing is formed to retain the vane assembly so that almost no contact abrasion will take place and the noise is minimized and the rotational speed can be increased. The cooling fan structure is manufactured at low cost and can be easily assembled.
FIG. 1 shows a conventional cooling fan with ball bearings, including a vane structure 11, a magnet 12, a stator 13, a sleeve 14, a circuit board 15, two ball bearings 16, a thrust spring 17, a thrust washer 18 and a housing 19. The ball bearings 16 serve to retain the vane structure 11 in operation. In high speed operation, the central shaft of the vane structure 11 contacts with and abrade the ball bearings 16. This leads to great noise and makes it impossible to increase the rotational speed.
Moreover, most of such cooling fans are used inside a computer for cooling the electronic elements so that such cooling fan has small volume (the cross-section thereof is generally smaller than the top face of the central processor of the computer, that is, smaller than 12xc3x9712 cm). As a result, the bearings employed in such cooling fan have even smaller volume. Therefore, the bearings must have very high precision so that the cost is relatively high and it is troublesome to assemble the bearings.
It is therefore a primary object of the present invention to provide an improved cooling fan structure. In which, the vane assembly and the fixed base seat contact with each other at one single point and an air bearing is formed to retain the vane assembly so that almost no contact abrasion will take place and the noise is minimized and the rotational speed can be increased.
It is a further object of the present invention to provide the above cooling fan structure that is manufactured at low cost and can be easily assembled.
The present invention can be best understood through the following description and accompanying drawings wherein: